Oil and natural gas wells often utilize wellbore components or tools that, due to their function, are only required to have limited service lives that are considerably less than the service life of the well. After a component or tool service function is complete, it must be removed or disposed of in order to recover the original size of the fluid pathway for use, including hydrocarbon production, CO2 sequestration, etc. Disposal of components or tools has conventionally been done by milling or drilling the component or tool out of the wellbore, which are generally time consuming and expensive operations.
Recently, self-disintegrating or interventionless downhole tools have been developed. Instead of milling or drilling operations, these tools can be removed by dissolution of engineering materials using various wellbore fluids. Because downhole tools are often subject to high pressures, a disintegrable material with a high mechanical strength is often required to ensure the integrity of the downhole tools. In addition, the material must have minimal disintegration initially so that the dimension and pressure integrities of the tools are maintained during tool service. Ideally the material can disintegrate rapidly after the tool function is complete because the sooner the material disintegrates, the quicker the well can be put on production.
One challenge for the self-disintegrating or interventionless downhole tools is that the disintegration process can start as soon as the conditions in the well allow the corrosion reaction of the engineering material to start. Thus the disintegration period is not controllable as it is desired by the users but rather ruled by the well conditions and product properties. For certain applications, the uncertainty associated with the disintegration period and the change of tool dimensions during disintegration can cause difficulties in well operations and planning. An uncontrolled disintegration can also delay well productions. Therefore, the development of downhole tools that have minimal or no disintegration during the service of the tools so that they have the mechanical properties necessary to perform their intended function and then rapidly disintegrate is very desirable.